apple canker

We moved to a new house this spring and inherited a lovely mature apple tree in the backyard. It's never been pruned and I set about doing both summer and winter pruning this year. Much to my horror (and panic) I just discovered a huge canker on one of the branches (right where it intersects with another branch), so it's essentially affecting two large branches. I have no idea what to do- it looks very severe and pruning it out will essentially mean removing both branches (and something like 1/3 of the whole tree). We still harvested loads of apples this autumn, so it's still fruiting, despite the canker. Any advice will be most gratefully received!

Hi PP, there's not much you can do other than the options you've already considered - either cut the affected branches out or live with it. Canker is not usually fatal on a mature tree so just keeping an eye on it would be my advice. If growth dies beyond the canker you will have to remove the affected parts - if you can cut it back to another branch lower down the limb do that otherwise the whole branch should come off at the trunk. The other possibility is to start a replacement tree in a large tub now with a view to removing the old tree and replacing it in a few years. You could even try grafting a healthy scion from the old tree onto the new one if you don't want to lose it completely.

they may help a little but there is no cure as such. A lot of the chemicals mentioned are no longer available though. Any time over the winter while the tree is dormant is fine for pruning out the damaged areas which I think is probably your best bet if you want to try and save the tree. Hard pruning will encourage lots of 'water shoots', most of which you'll want to remove in the summer, but you can let a few develop into new branches and fruiting spurs. Advice from the RHS on this (called 'renovative pruning') is here: